IGTI conference concentrates on helping the gas turbine user
With the theme “Maintain the Edge for the User“ the recent IGTI
conference emphasized the commitment of gas turbine manufacturers to put customers first
By Hank Stein,
Everyone seems to be concerned with “the customer” these days, and those at the 39th ASME International Gas Turbine & Aeroengine Congress/Users Symposium & Exposition (Turbo Expo `94) were no exception. In fact, the theme of the June Turbo Expo was “Maintain the Edge for the User.”
The American Society of Mechanical Engineers (ASME) estimated approximately 6,000 attendees heard this theme repeated throughout the 400 papers presented at 112 sessions and workshops in the conference.
Keynote speakers stress gains
The concern for customers must be working for gas turbine sellers, as evidenced at the Turbo Expo `94 keynote session, where Jannes J. Verwer, N.V. Electricteitsbedrijf Zuid-Holland general manager, pointed out that, “Every unit built in the Netherlands between now and the year 2000 will incorporate gas turbines.”
He was indirectly backed up in this assessment by J. Veenema, Elekticiteits-Produktiemaastchappij (EPON), the Dutch utility, who illustrated how gas turbine use had increased in recent years in Holland. Veenema said that in 1980, 20 machines in the country were producing only 600 MW of electricity. By 1990, this total reached 57 gas turbines producing 2,400 MW.
Veenema predicted the turbines would produce 5,000 MW in the Netherlands by the year 2000, meeting 30 percent of the country`s needs.
“I want to build a bridge between (gas turbine) manufacturer and user,” Verwer said. The “bridge” he proposed was a partnership. He defined this type of partnership as the customer and supplier taking risks together.
To facilitate this, the supplier has to be candid about the strengths and weaknesses of the equipment so the user can make the best possible estimate of the expected lifetime costs and reliability. The customer has to be willing to try out new equipment and be frank about project needs.
Another of the keynote speakers, Rolf Kelhofer, ABB Power Generation president, agreed with this stance, but looked at it from a slightly different viewpoint.
“The traditional clear distinction between suppliers and users is no longer as clear as it used to be. All kinds of partnerships are emerging, with one common goal: stay in the business and make a good profit,” said Kelhofer.
He described the situation as “vertical integration of the business.” Among the ways gas turbine suppliers were vertically integrating were by supplying turnkey power plants, helping in operations and maintenance, and in structuring and financing new projects.
Keynote speaker lists advantages
Kelhofer listed the advantages gas turbines had that especially pointed to their increased usage by independent power producers (IPPs). The advantages were:
– low first cost,
– low environmental impact,
– high efficiency, especially with combined-cycle plants,
– short construction time,
– easy operation,
– good suitability for cogeneration, and
– a secure fuel supply.
These advantages were risk-reducing factors that were important for project-financed plants whose developers were driven by a desire for a high return and a high debt-to-equity ratio, according to Kelhofer. However, a private utility could have the same target for return on capital as an IPP.
Kelhofer made a plea for sharing the risks related to new products. He said the new trend toward IPP and privately-owned utilities did not support quick introduction of new technologies into the marketplace. Traditionally, utilities in Europe, the United States and Japan were ready to take on a share of the risk associated with new products. Project-financed plants were only accepting new technologies provided the supplier assumed the risk. The financial risks associated with large projects were such that even very strong companies could not shoulder them by themselves.
Future user demands
Stig Gothe, vice president of Vattenfall AB, the Swedish utility, listed the features electric power users would expect from gas turbine manufacturers in the future as:
– equipment availability and
– maintainability will remain
– as important requirements,
– good environmental performance
– is expected, without using
– additives and catalysts,
– gas turbines should accept fuel
– gas with low heating value
– from gasified solid fuels, and
– combined-cycle and integrated-
– gasification combined-
– cycle (IGCC) plants should
– have increased flexibility so
– they can be integrated into
– different industrial and
– cogeneration processes.
Gothe felt the gas turbine would become the central, and most important, prime mover in power plant technologies in the decades ahead.
A new feature of the turbine conference was the Users Symposium, held at the end of the last day of Turbo Expo `94. A wide gamut of gas turbine users was represented at the symposium, from specifiers and purchasers, to operators and maintenance personnel, to engineering and construction firm people. They were there to share information and viewpoints about their applications of gas turbine technology.
Among the panel speakers was G.N. van Ingen, of the Dutch utility AKZO, who expressed his concern with the emphasis placed on catalytic reduction systems for reducing NOx emissions from the turbines. Van Ingen said more emphasis should be placed on finding ways to reduce emissions “on the front end.”
Another panelist, Veenema, told how gas turbine usage had increased in recent years in the Netherlands.
The status of IGCC plants brought forth a sharp difference of opinion between the chairman of the IGCC-Lessons Learned session and his panel. Chairman R.L. Bannister of Westinghouse Electric Corp., in introducing the session, stated the process was not yet commercial. The first panelist, Paul Curran of Texaco Syngas Inc., was quick to dispute the chairman`s statement. Curran declared unequivocally that IGCC was commercial now. He also said commercial experience included syngas production of 2.8 billion cubic feet of gas per day. He then described how commercial the process was and that it was the cleanest method for utilizing most “dirty” fuels.
Curran pointed out there were 37 plants operating worldwide at that time and 14 more in the engineering/construction stage.
James Garstang of British Gas plc discussed the Lurgi gasifier his company had operating, processing 200 tons of fuel per day. Leroy Tomlinson, General Electric Co., said his company was developing power systems to be compatible with IGCC. He described the Cool Water project in the United States that operated for five years and could meet the Southern California stringent air quality requirements. However, the project was not economically feasible.
Coal gasification in Holland
George Zon, project director for Demkolec B.V.`s Demo KV-STEG coal-gasification plant, reported on progress at the plant in Buggenheim, the Netherlands. The 250-MW plant, which started up in early 1994, can convert up to 2,000 tons/day of coal into synthetic gas. A three-year demonstration project was planned to gather relevant data about the characteristics of the IGCC process.
Gasification technology is based on a Shell license. The gasifier uses 95 percent pure oxygen from an air separation unit. Solids removal is by a cyclone unit and ceramic filter.
Flyash is recycled to the gasifier through the coal mills. The syngas cooler generates medium- and high-pressure steam, both slightly superheated. Nitrogen, also from the air separator, is used to pressurize the coal and dilute the clean coal gas.
The final coal gas composition is approximately 65 percent CO2, 30 percent H, 1 percent CO, 1 percent H2O, and 3 percent N and Ar. Desulfurization efficiency is 97.9 percent and NOx production is lower than 75 grams/gigajoule of coal. Dust emitted is negligible.
Plans were to reduce SO2 emissions to a desulfurization level with 99.5 percent efficiency, increase coal-to-power efficiency to 48 percent, investigate scaling up the plant to 400 MW, and simplify the plant throughout.
Hot-gas cleanup in United States
Westinghouse Electric Corp. reported on investigations of hot-gas cleanup to protect the combustion turbine and environment from emissions generated during coal conversion in a gasification-combustion system. The basic principles presented included utilizing ceramic barrier filters for multiple cleaning functions, particulate removal and sorbent-contamination reactions, and using relatively fine sorbent particle sizes for improved reaction performance.
R.A. Newby and R.L. Bannister, Westinghouse, maintained that commercial cleanup systems for present-day coal-based fuel gases operated at temperatures near ambient and required large heat-exchange equipment. They also maintained that low-temperature cleaning resulted in power plant costs and efficiencies that were only marginally better than conventional pulverized-coal boiler plants.
Hot-gas cleaning systems under development would operate at temperatures up to 1,700 F (926 C) and these systems were nearing the commercial demonstration phase. Calculations indicated calcium-based sorbents operating at 1,600-1,800 F (870-981 C) could achieve at least 90 percent sulfur removal and an emission rate of about 0.6 lb/MMBtu SO2.
Zinc-based sorbents, which have the highest sulfur-removal performance, could operate at about 1,300 F (704 C) and copper-based ones could meet power plant goals of 0.18-0.2 lb/MMBtu SO2 emissions at temperatures of 1,600-1,700 F (870-926 C).
The Westinghouse preliminary hot-gas cleanup design consisted of an integrated, single train of shop-fabricated vessels. The primary stage sulfur-removal sorbent was calcitic limestone, while the polishing sorbent was copper-based.
Estimated installed costs were calculated. For a fluidized-bed process with air, the capital requirement would be $297/kW and the cost of electricity 19.0 mills/kWh; for one with oxygen, $255/kW and 17.4 mills/kWh; and for an entrained bed with oxygen, $233/kW and 17.6 mills/kWh.
Using nuclear warheads
Nicola Cerullo and Giovanni Guglielmini, Universita de Genova, and A. Di Pietro, ENEA, proposed using fissile materials recovered from dismantled nuclear warheads in civilian power reactors, in particular, recovered highly enriched uranium and thorium in a uranium- thorium reactor. They also suggested that recovered plutonium could be utilized in liquid-metal fast-breeder reactors.
Cerullo and Guglielmini noted that ENEA had reprocessed and refabricated 233U in experimental processes at its Nuclear Research Center. Further, they postulated that the high-temperature capability of the high-temperature gas-cooled reactor, and the small size and high reliability of high-pressure gas turbines presented an appealing combination for an efficient Brayton cycle.
A uranium-thorium cycle in a high-temperature gas-cooled reactor would be fueled by 93 percent 235U from the warheads and 232Th. The process would convert the 232Th into 233U, which could power the reactor. The final byproduct would contain only a small amount of non-military-grade plutonium. The authors postulated high performance of the reactor-gas turbine combination produced at low cost.
Lean-premixed cycle emissions
Speakers from United Technologies Research Center (UTRC) and the Pratt & Whitney Division of UTRC told of their development of a dry low-NOx, high airflow-capacity fuel-injection system for a lean-premixed combustor for a moderate-pressure-ratio (20-to-1) aeroderivative gas turbine.
They evaluated combustion performance at high power conditions in a high-pressure, single-nozzle test facility operating at baseload conditions.
Single-digit NOx levels and high combustion efficiencies were achieved. They also demonstrated a wide operability range with no signs of flashback, autoignition or thermal problems. NOx sensitivity to pressure and residence time were small at flame temperatures below 2,870 F (1,850 C).
Five high-penetration injection sites per inlet produced the desired NOx control. NOx performance and operability for the nozzles was insensitive to nozzle pressure drops down to 2 percent and inlet air temperatures ranging from 590 C to 700 C.
ASME Turbo Expo `95 will be held in Houston, Texas, USA, June 5-8. For information contact Nelson L. Sanger, NASA Lewis Research Center, 21000 Brookpark Road, MS 5-11, Cleveland, Ohio 44135, USA, phone (216) 433-5856, fax (216) 433-3000.
Combined-cycle Puchon power plant in Seoul, Korea, produces 450 MW from 501D5/ST gas turbines. Source: Westinghouse Electric Corp., U.S.A.
This 117-MW combined-cycle plant in Linz, Austria, began commercial operation in September 1993. It is based on two MS6001B gas turbines. Source: GE industrial & Power Systems, U.S.A.
Combined-cycle district heating Nossener Brucke plant in Dresden, Germany, uses three V64.3 gas turbines and will generate 480 MWt and 260 MWe when completed. The first units go on-line this winter and the last by the end of 1995. Source: Siemens Corp., Germany.
Construction was still under way on these FT8 twin pacs on Hainan Island, China. The 100-MW plant began operation in May 1994. Source: United Technologies Turbo Power, USA.
Silo combustor is lowered into place on a GT13E gas turbine at National Power`s 652-MW Killingholme power station. The station began commercial operation in July 1993. Source: ABB Power Generation Ltd., Switzerland.